DVCAM v DV?

DV vs. DVCAM

They are both DV25 formats. DVCAM is Sony's 'professional' DV25 format which records at a slower speed (less time on tape) than DV, but also records locked audio -- which means the audio clock is synched to the video -- which means no audio drift over time, as you get with DV/miniDV.

tim

DVCAM actually runs the tape faster than DV, but you get Tim's point. 🙂

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right -- doah! DV runs slower that DVCAM. (are you confused now?)

tim

I posted a very similar question over at sonyhdvinfo.com. My question was in regards to if I should shoot in SD at all, or stay in HDV all the time and then if I just want SD to edit and output in, downconvert from the camera upon import. I also asked about DV vs DV CAM and this was the reply by Klenkfilm: "DV and DVCAM have the same image quality and compression, anything else is indeed a myth. Some other differences apply, like tape speed. Always shoot HDV, and use the downconversion if you need DV/DVCAM for editing.

DVCAM is more robust in terms of drop-out risks, but these initial problems of early HDV machines seem to have vanished completely. People have learned not to use the cheapest tapes on the planet. And DVCAM has better sound, but that's also theory - finding someone who can tell the difference in a "blind" test (location audio, location dialogue) will be very hard if impossible." So I'd stick with either regular DV or for me, always HDV and not worry about changing formats, ect.

-Brian

For what it's worth, the BBC suggest (or at least they did when I left last year) not down converting as the drop out risk is much greater when shooting in HDV - it's not that you're more likely to get drop out, just the consequences are greater. (I'm now about to write stuff I only just understand but I'll carry on anyway)

HDV is made possible by using a 12 frame group of pictures or 'GOP'. That means that each frame is based on an original source frame that could be up to 12 frames prior to it. If you lose that original source frame due to drop out, you can lose half a second of material rather than just a frame or two.

Frankly, whether you lose a two frames or 12 will generally still leave the material useless but you can see why there is nervousness about the risk.

For that reason I've always adopted the BBC principle of shooting in DVCAM for SD shoots and only shoot in HDV when I need HDV material. Also on a practical level I have a DSR45 and don't want to hook the camera up everytime I need to digitise.

However, it's interesting to hear people who are sticking with HDV without a problem. You may force me to finally shake off my BBC background.

As for DV v DVCAM. I agree there is no quality difference that people without elbow patches and who really understand what a GOP is will be able see. However, I think the main issue is tape quality. I'm told the proper Sony DVCAM tape is more robust than mini DV and will last longer in the library if that is an issue for you? Could just be Sony marketing but it has worked on me!

Horse for courses and all that!

Regards
Richard

The HDVvDV/DVCAM issue is all about drop out and the '12 frame GOP'

Yep, you've got it Richard. Quality is identical between DV and DVCAM, visually and aurally -- exactly the same. The two big things that separate the two are the locked audio issue, and that DVCAM uses more tape to more-reliably record the signal.

As for the tape and dropouts...the cheapest DVCAM tape is not as bad as the cheapest miniDV tape. In other words, tape manufacturers offer lower-quality tape in mini shells than in the large shells labeled for DVCAM. If you shoot miniDV on good tape -- tape meant for HDV is made to a higher standard (like Sony's PHDVM-63DM Digital Master), dropouts will pretty much be a thing of the past ( *disclaimer* I make no guarantees, so don't hold my feet to the fire! 😉 ). But in my experience, those DM tapes are exponentially better than those $3.00 Walmart tapes when shooting miniDV (that's like 2.50 for you chaps across the pond, right?).

HDV requires good tape to reduce the chance for dropouts, since it uses intER-frame compression with a GOP length of half a second (and over here we have a 25% higher risk for dropouts with a GOP of 15). If these GOPs look a little familiar, they are also implemented in DVD production, but that's another forum.

The HDVvDV/DVCAM issue is all about drop out and the '12 frame GOP'

Yep, that about sums it up.

tim

Simply put, there's no reason to cheap out on tapes. I got a free Digital Master tape with my HVR-A1U and I waited to use that for my graduation. As far as other recordings, I use the aforementioned Sony HDV tapes. You pay a premium for them, but that gives me a reassurance since they're designed for my camera by the camera maker. I'm not sure I'd ever buy other brands or cheap tapes, and probably not even the basic miniDV tapes from sony just cause they're not made for HDV recording. I'm sure we could get into a whole debate as far as tape stock to use, but simply put, if you're using a quality tape, dropouts shouldn't be an issue no matter what format you're recording in. And lastly, to add my $.02 to the HDV and downconverting dropout issue, I've imported my fair share of HDV content, and never had a dropout.

Good Luck,
-Brian